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MG Midget and Sprite Technical - Midget engine flooding?
| Hi, Over the last few weekends of prepping my 1500 for sale, it has gone from only running on the choke to not starting. I last had it running about 6 weeks ago, but only on choke and if you touched the throttle the engine would immediately die. Now the engine won't start at all on choke. If I pull the choke for a few seconds out whilst turning over, then push it back in, the engine gives a few coughs as if it is trying to catch, but won't. If I try and then tease it into life with a little choke or throttle, it seems to flood again. So I suspect flooding, but can anyone help me with the likely cause? I'm generally technically savvy and have some basic tools, so can tackle most simple stuff. When I ran the car it was maintained by a local classic car specialist who has now gone, so whilst I have a good knowledge of cars/engines etc I don't know any of the specifics about common problems. It's a standard 1976 midget with twin HS4 SU with the side-mounted float chambers. |
| S Greer |
| With early HS4's, which IIRC don't have separate overflow tubes, flooding is predominately caused by the needle valves in the float chamber not closing properly as a result of crud picked up in the tank. Try removing the float chamber lids, clean the valves and any crud in the bottom of the bowl and try again. If you don't already have one, adding an inline filter may help. PM me if you want on-site help Best of ... MGmike |
| M McAndrew |
| wrong thread, retracted. |
| Lawrence Slater |
| The little tubes that run from the bottom of the float chamber to the bottom of the carbs are clogged up Spray can carb cleaner with a straw and a large paper clip is your friend The tube is called the jet... There are online sources that will tell how to remove and reinstall and adjust as well as a haynes manual and maybe an owners manual ??? In the future, dont let the fuel tank get to empty before refilling and do a double inline filter with see thur glass about 6 and 12 inches from the carb... 1 large and the 2nd smaller Good luck... Let us know what happens Prop |
| Prop and the Blackhole Midget |
| Wow, that was fast! Thanks everyone, great responses! MGmike: Thanks for the advice. I'd read elsewhere of the problem of sticking or clogged needle valves, so today I tried a sharp rap on each float chamber to see if this would free things up without the need for disassembly. It didn't start, but it was trying a bit harder! Taking the lids off the float chambers is a screwdriver job, so I'll try that tomorrow. Prop: I have a Haynes manual, but there isn't much on the float chamber in there and the diagram only shows part of it. Unusual, because those manuals generally have every detail. So thanks for the heads-up on the jets, I might have missed them when cleaning the rest of the chamber. All of this would be much easier if I hadn't stupidly driven the car nose-in to the garage last time I had it out! It didn't occur to me that I wouldn't be able to jump-start it and as there is a steep ramp down into the garage, I couldn't push it out! Doh! |
| S Greer |
| Geer... I dont belive its the needle valve in the float chamber...if it was, the issue would be imediate, your issue was long term and got worse over time .... Normally it will also shoot fuel out the vent hole when running if the needle.valve is sticking You will need to remove the jet from the bottom of the carb...then unbolt the float chamber from the carb, this will get you easy access to the inside of the jet tube to clear the blockage...you will need a manual to show how to assemble and re-.set the carb...or a helpping experianced hand |
| Prop and the Blackhole Midget |
| I forgot to mention... the choke has no influance over the needle valve in the float chamber lid....other then to draw down the fuel a little faster out of the float chamber Prop |
| Prop and the Blackhole Midget |
| The choke enriches the mixture. The fact that your engine ran better with the choke on suggests that your problem is with an abnormally lean mixture. A stuck open float needle valve would cause a rich mixture (flooding), and using the choke would only make it worse. It could be a stuck *closed* float needle valve- though that's rare, and usually concurrent with a failing fuel pump. Might be a good idea to check your oil- it may be filling with petrol if you have a mechanical fuel pump. I'm with Prop on this one, there's probably a blockage between the float chamber and the jet. But check your oil for petrol contamination too, just in case. |
| Growler |
| Good call growler.... I didnt think of the1500 mechanical fuel pump as an issue....id think just pulling the oil cap and sucking in a good wiff for fuel smell would work wouldnt it ??? |
| Prop and the Blackhole Midget |
| I'd be surprised if it's the fuel pump, but it's worth sniffing the dipstick just in case. My other thought is that leanness might be caused by an air leak, perhaps the carbs or manifold coming loose, a failed gasket, or missing anti-pollution pipe. But with all the fiddling about near the carbs that sort of thing would be fairly evident. |
| Growler |
| You could try this link for some very useful info http://www.sucarb.co.uk/Technical.aspx |
| Nigel Axtell |
| Thanks again everyone for the suggestions. Didn't manage to get into carbs today as local shop didn't have gasket paper in stock. I should point out, with regard to possible failures, the car has gone nowhere for 5 years. It's been in my garage and get's a battery charge and the engine run up to temperature about twice a year. It's only the last few times I've started it that it didn't run perfectly and settle into an even 650rpm idle! I did run it out if fuel once, so that's why I'm leaning more towards dirt or some kind if contamination rather than a component failure. The car hasn't been subjected to any effort, or had anything disturbed or messed around with, so I'd be surprised if there is any failure other than a 'static' type from deterioration. |
| Stevie Midget |
| Wonder why I was my real name now my user name! |
| Stevie Midget |
| just go into Customise and change it when you want/need why did it happen - because it's a computer and it can |
| Nigel Atkins |
| I think you're right, dirt in the lines is the likely culprit. "the car has gone nowhere for 5 years" In that case, even if it's not the fault this time around, keep an eye on that fuel pump. The rubber diaphragm can perish and split, pumping fuel into your engine block. |
| Growler |
| Clyde Barrow: Now you just tell me what was wrong with that car. C.W. Moss: Dirt. Clyde Barrow: Dirt? C.W. Moss: Dirt in the fuel line... just blowed it away. |
| Lawrence Slater |
| Depending on how recently you ran it out of fuel..if it was a couple of years since you put more fuel in, then the fuel could have lost it's volatility and fuel that wont ignite gives all sorts of weird symptoms such as blocked jets etc, which could of course also be true. If you have not already done so, I think a nice fresh fill of enough fuel to start it, pumped through to the carbs would be a wise step. If you could syphon out the old stuff first would be a help, and you could put it back in small amounts later to use it up. If you have not "fiddled" since it last ran, then the cause of not starting has be be something that has deteriorated in the mean time, and fuel certainly doesn't last forever. |
| JB Anderson |
| If the fuel is stale and close to starting on empty the contamination may well be from condensation adding to the low volatility of the fuel.Typically an engine will start but have an inability to rev cleanly - then splutter and die. Fresh fuel gets my vote. |
| F Pollock |
| Most interesting! I've been adding fuel every now and then over the years when required. The last lot was a new gallon straight from the station, but it was on top of maybe a gallon or two of stuff that was up to 5 years old. I'm gonna try this first as it's easiest and cheapest, plus I your symptoms are exactly what I've been getting. Thanks again everyone. I'll get to it when the hailstones stop! |
| Stevie Midget |
| Do you ever get the feeling theres a cosmic joke and we are always the last to know what the heck is really going on Storing in a garage for 5 years and running out of fuel while starting it once every year.... Is something that would have been nice to have known like ...on the 1st posting Hey.. i cant get my engine to turn over... We say try this this and this...30 postings later... Do i need a battry... I dont have one ... Will a Durecell AAA work ? Come on S. Geer...throw us a bone, we are not all carnival mind readers here, thats a completely differant midget site what else have you NOT told us. Im now adding sticking valves to the now growing list...as new info is being added...compression test is now needed Is the garge.heated and do you have ANti mix in the engine/ radiator of at least 50/50...if not, cracked head / block is next on the list Prop |
| Prop and the Blackhole Midget |
| You in bad mood Prop? |
| Lawrence Slater |
| There's always one who thinks it's a competition! Prop, a post of 500+ words detailing the car's life history prior to not staring would have (in my experience of forums) have attracted precisely zero responses. Don't worry, if you answer turns out to be correct, I will be most thankful. I can send u a little cup or medal if that helps? Chill out! |
| Stevie Midget |
| I've not seen a post from Prop for several days that hasn't had me instantly laughing you just have to be in the Prop zone - and then try to escape S Greer, you might not need to but just in case, when you do finally get it moving if it hasn't moved for 5 years be aware of possible faults with old unmoved tyres, brakes - rusted on, wet fluid, perished seals, handbrake, seized clutch, suspension and bushes, electrics, damp and rust I'm h a pp y, I'm h a pp y . . . |
| Nigel Atkins |
| Yeah....ive been really pissed off all day. Just tired, and patiance is just worn thin. I am in the wrong...offence was intened at the time, but now im regretting the harshness of my comment Nigel has a real point....with sitting for 5 years this car.may well have some issues... You may want to consider selling the car AS IS, and not doing anything other then a tow truck to remove it from the shop and a good garden hose washing...id fear it could cost more to repair all the damage.from sitting then you would get from the sale of the car You may want to consider keeping the car if you repair it...they are fun Prop |
| Prop and the Blackhole Midget |
| Lecter for president ? Hmmm Id perfer him as speaker of the house of congress....Haha Now that would be a game changer Gez that would be funny...instead of some big spending bill to be aproved by the senate, he would send up livers and brain gizzards with wild turkey wiskey and lima beans...( gov cant afford the good stuff) In the movie the manhunter....i cant remeber exactly but wasnt it less about haniable lecter and more about the hunt for wild bill because it wasnt lecter that fell in love with the blind girl and was watching his handy work on 8mm film on there house dates. In that film lecter was still a good guy but conflicted with the call on his inner demon |
| Prop and the Blackhole Midget |
| If they ever made a prequel of silence of the lambs... That explored the conversion of lecter and his exceptance to his true nature and purpose in life ... Id love to see edward norton play lector and the teenage version of anikin skywalker ( darth vader) as wild bill and the good looking black woman MEdical exaimer from CSI miami as wild bills blind girl friend and take the movie up to the point of the introduction of clarise and and end it there before the capture of wild bill ...so the movie focases souly on lectors connection and fascination to wild bill and ultimatly lecters spiraling downfall into mental illiness...basically the film focas more on wild bill as the mentor / educator to lecter...the trick is how do you make wild bill fill that roll when he is portrayed as your typical serial killer of avg to low intellagence low motivation and few accomplshments...unless you suspend reality make wild bill into a hidden high intellect that uses his hidden intellect to his advantage and its lecter that discovers that hidden intelect and thus the blissoming friendship/mentor/educator connection ... You could even take the story to the ultimate potrayal that lecter does to wild bill Omg... You could use the judis / jesus christ senerio as a templete with wild bill as the JC and lecter as judis....remeber as a story templete...NOT a litairy part of the film Considering lecter was a mental theripist at the time he was introduced to wild bill, holiwood really .needs to understand menal illiness or even this filmwould become completely retarded fast...but what a great film potential this could have if it was done well with the right people and less holliwood intervention....do the film in blue background lighting with a very melicollie string section music sound track. More mental and less gore... An intellagent thinking film There is NO way hollywood will ever make this film...maybe an experianced independant...but gez what a film that could be |
| Prop and the Blackhole Midget |
| So.....syphoned as much fuel out as I could (now I'm burping petrol...you always swallow a bit no matter how careful!). Replaced with 2 gallons of super, with a double-dose of redex carb-cleaner. Slighty better, but still won't start, although this time it threatens to start on choke. Hmmm, so it's maybe the stale fuel AND some dirt or gum in the carbs. I'm tempted to fire a can of spray carb cleaner before resorting to taking the carbs of for cleaning. Prop, I don't get offended on forums, no harm done :) For anyone whose interested. Yes, I do like the Midget. I used it as summer transport for 3 years and it was very well maintained by a specialist for the bits I couldn't do. The car is mechanically very good and I think the amount of work done on it just prior to going off the road has been worth it. Prep so far: All tyres removed and wheels rust-busted with wire brush, tyres refitted (inc 2 new ones) Points removed, checked and cleaned, fitted and gapped. Condenser checked with meter, rotor arm and cap checked and cleaned, coil checked and contacts cleaned. Plugs checked and gapped. New battery fitted. Earth cable removed, cleaned, refitted. Brake lines checked for leaks, fluid topped up. New brakes fitted not long before storage so no problems there. Suspension springs, shocks, bushes and joints checked, all appear fine. Again, the car had a big service with all grease points done before storage. The car itself has been previously restored by an MG/Rover mechanic. in 1997. I have a photographic record given to me when I bought the car. New floor, wings, inner wings and all the other common rusty bits repaired ad the whole thing resprayed BRG. It's structurally good, but because the car sat through two winters under a 'waterproof' cover, it now has surface rust on all the usual places. The only bit of welding I can see it needs is the top of the driver's B pillar where there is hole under the chrome cap. The reason I'm not selling 'as is' is because it's too good a car for that. I want to do the car justice by selling it as (demonstrably) a runner, although i wouldn't let anyone drive it away. It will be an easy restoration for someone, as it really only needs a hood, new bonnet, exhaust back-section and the paintwork done. It has leather-faced seats in the original pattern, new carpets, sound-proofing etc. |
| Stevie Midget |
| Prop, I don't get offended on forums, no harm done :) No problem, crap for brains..... hahaha, sorry i couldnt resist the temptation I still belive its gunk inside the tubes....you might try this,im not sure how well it will work...but simple enough to try and wont disturb the carb settings Get the spray carb cleaner but with a long thin straw ... Remove the 3 screws that holds the dashpot on, and remove the dash pot, then carfully catch remove the spring... Dont be tempted to stretch and do anything to the sprinf then carefully lift the piston straight up its the part that the spring sits on top below it will be a long brass spike... Do mot disturb it kepp it untouched as much as possible and attached to the piston ... Now take the float chamber lid off the float chamber and remove the fuel and dry as much as you can... Dont drop or loose the float needle inside the float lid Now use the spray carb cleaner and put the straw down the hole that the long brass spike was fitted into and spray away... Try a long piece of soild copper electrical wire to help push and brwak up the clogg when the carb cleaner pblast thur into the float chamber without restriction its done As haynes says... Assembly is reverse the order of disassmbly...then do the 2nd carb Prop |
| Prop and the Blackhole Midget |
| The trick will be to get the straw into the small hole of the tube..my guess is the blockage will be at the beginning of this procedure...so it may take some effort to push the gunk back thur the tube and back into the float chamber...plan an hour per carb and only do one carb at a time. Prop |
| Prop and the Blackhole Midget |
| I just dont know thats going to work... Im thinking the seat that the jet tube fits into maybe to small a diameter for the straw to fit thur... And the seat is inserted from the bottom of the carb Id say lets get the opinion of the group 1st...im going from memory and i dont know alot about the HS4 specs |
| Prop and the Blackhole Midget |
| Hey Prop. I think your brains are scrambed eggs on toast today. lol. Lecter was appearing in another thread. "1275 cc poor running" Still I like the bit about " -- he would send up livers and brain gizzards with wild turkey wiskey and lima beans...( gov cant afford the good stuff) -- " Everybody else must think you've really lost it, if they haven't read the other thread. hah hah hah :) Sorry Stevie. Back to the flooded Midget now. |
| Lawrence Slater |
| OH...GEZ, Good god... I should never even gotton out of bed this morning...thanks lawerance i screwed that one up...to much trash on the brain I guess Now would be a good time for a non time aloted edit botton... I think this what is known as screwing up a wet dream...hahaha Prop |
| Prop and the Blackhole Midget |
| Lawerance Would what i was proposing above work about cleaning the gunk out of the tubes... I know for fact the thin straw will fit into the jet, but im not sure about the adjustable seat ... Do you have insight....considering the needle goes thur with out issue... I guess it would Work. Prop |
| Prop and the Blackhole Midget |
| Might do, but it depends what it's blocked with, or if it's just stale fuel. |
| Lawrence Slater |
| Steve Midget, as usual I’m just pointing out - >>Earth cable removed, cleaned, refitted<< battery or engine or both >>New brakes fitted not long before storage so no problems there<< I’d don’t know/can’t remember – how long before unused pads/shoes go hard or perhaps the surface scrapes clear with use >>all grease points done before storage<< so old unmoved grease, I’d pump that out to replace with new, grease doesn’t remain fully effective for ever >>restored by an MG/Rover mechanic. in 1997<< that was 15 years ago >>it now has surface rust on all the usual places.<< some garages are very good at holding damp and condensation and a cover can help to hold it in the car further – plenty of fresh air is required, did you also put carpet or matting under the car >>sound-proofing etc.<< look under soundproofing for damp and wet as you know it should only be fuel or electric why it won’t start unless various things combined are preventing it firing, perhaps a manifold leak or sticking carb is just adding enough to any other weakness – a fully charged battery is a must to help regardless of age have you checked spark power in and out – other non-starter threads in Archive as always step by step logical diagnostics is required |
| Nigel Atkins |
This thread was discussed between 21/11/2012 and 24/11/2012
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